This invention generally relates to off-board navigation or route guidance systems and, more particularly, to a system that transmits a filtered map area including a recommended route and desired points of interest.
Navigation systems generally provide a recommended route to a desired destination. Generally, the desired destination is selected from a large database of roads stored in a mass media storage, such as a CD ROM, which includes the roads in the area to be traveled by the user. If the navigation system is installed in a vehicle, the starting point is typically associated with the vehicle position and can be input to the navigation system by an associated position determining system that usually includes a GPS (Global Positioning System) receiver.
Vehicle navigation systems include many expensive components, including a CPU with mass storage, such as a hard drive, CD or DVD, memory compact flash and RAM for storing a map database. It is therefore known to provide so-called “off-board” systems which primarily include a supply location. The supply location includes a processor that actually calculates a recommended route based upon a request from a remote unit such as a vehicle. The supply location further includes an extensive database of roads and points of interest (POIs). The supply location database is frequently updated and can include transient events such as accidents, road construction, weather issues, and the like. Further, because the supply location is not actually within the remote unit, size, weight and expense are of minimal concern. Communicating with the supply location also allows a reduction of navigation system components which must be installed within the remote unit. Moreover, only minimal processor and storage capabilities are required in the remote unit as these functions are performed off-board at the supply location.
In response to a request from the remote unit, the recommended route is sent to the remote unit and displayed to the user as a map showing the desired destination and highlighting the recommended route. The on-board navigation system will then autonomously guide the driver to the selected destination based upon the information sent from the supply location. Preferably, if the navigation system is installed in a vehicle, the on-board navigation system displays the current position of the vehicle and provides visual turn-by-turn instructions to the driver based upon position and motion determining devices located within the remote unit.
One known off-board navigation system requires the remote unit to maintain the large database of roads stored in a mass media storage device. By maintaining the road database on-board, only the recommended route need be transmitted from the supply location to the remote unit. This is quick and efficient. However, this known system still requires the remote unit to carry a rather extensive suite of navigation system processor and storage device components which limits the advantages of providing the processing capabilities at a supply location. Further, the supply location may have a more recently updated database of roads than that stored in the remote unit. Difficulties may therefore arise in the application of a route calculated at the supply location to the older database stored in the remote unit.
In another known off-board system, the entire database of roads along with the recommended route is transmitted from the supply location to the remote unit. Although this known system assures that the most recent database is transmitted to the remote unit, a rather long period of time is typically required to transmit the database of roads and the recommended route from the supply location to the remote unit. Again, this known system also requires the remote unit to carry a rather extensive suite of storage device components to receive and store the extensive database of roads and the recommended route.
It is thus desirable to provide an efficient off-board navigation system which assures that the latest database of roads is available to a remote unit having a minimum of on-board navigation system components. It is further desirable to allow a user to request particular POIs to meet personal desires of the user.